dumpkmap.c

   1 #include <unistd.h>
   2 #include <fcntl.h>
   3 #include <sys/ioctl.h>
   4 #include <netinet/in.h>
   5
   6 #define KDGKBTYPE 0x4B33
   7 #define ARRAYSIZE(a) sizeof(a)/sizeof(a[0])
   8 static int console_fd(int mode) {
   9         const char devs[][16] = { "/dev/tty", "/dev/vc/0", "/dev/console" };
  10         size_t i = 0;
  11         int fd = -1;
  12         while(i < ARRAYSIZE(devs) && fd == -1) {
  13                 fd = open(devs[i++], mode);
  14                 char arg = 0;
  15                 if(fd != -1 && ioctl(fd, KDGKBTYPE, &arg)) {
  16                         close(fd);
  17                         fd = -1;
  18                 }
  19         }
  20         return fd;
  21 }
  22
  23 struct kbentry {
  24         unsigned char kb_table;
  25         unsigned char kb_index;
  26         unsigned short kb_value;
  27 };
  28
  29 #define KDGKBENT 0x4B46
  30 #define NR_KEYS 128
  31 #define MAX_NR_KEYMAPS 256
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #ifdef USE_LIBULZ
  36 #include <ulz/stdio-repl.h>
  37 #endif
  38
  39 #define noret __attribute__((noreturn))
  40
  41 noret static void die_perror(const char* msg) {
  42         perror(msg);
  43         exit(1);
  44 }
  45
  46 noret static void usage(const char *arg0) {
  47         dprintf(2, "usage: %s > backup.kmap\n"
  48                    "dumps current keymap to stdout.\n"
  49                    "redirect to file as output contains binary data\n", arg0);
  50         exit(1);
  51 }
  52
  53 int main(int argc, char** argv) {
  54         (void) argc;
  55         if(argv[1] || isatty(1)) usage(argv[0]);
  56         const char flags[MAX_NR_KEYMAPS] = {
  57                 [0] = 1, [1] = 1, [2] = 1,
  58                 [4] = 1, [5] = 1, [6] = 1,
  59                 [8] = 1, [9] = 1, [10] = 1,
  60                 [12] = 1,
  61         };
  62         int cfd = console_fd(O_RDONLY);
  63         if(cfd == -1) die_perror("could not get console fd");
  64         write(1, "hcukmap", 7);
  65         write(1, flags, MAX_NR_KEYMAPS);
  66         size_t i = 0, j;
  67         for(;i < 13; i++) if(flags[i]) for(j=0; j < NR_KEYS; j++) {
  68                 struct kbentry ke = { .kb_index = j, .kb_table = i };
  69                 if(ioctl(cfd, KDGKBENT, &ke)) die_perror("failed to get key setting");
  70                 unsigned short s;
  71                 s = htons(ke.kb_value);
  72                 write(1, &s, 2);
  73         }
  74         return 0;
  75 }